Office chair



FIG. 1 is a front perspective view of an office chair showing the claimed new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a right elevational view thereof;

FIG. 6 is left elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines represent the portions of the office chair that form no part of the claimed design. 

CLAIM The ornamental design for an office chair, as shown and described. 